The present invention relates to a plant cultivation method and an apparatus therefor for artificially cultivating a plurality of plants such as vegetables or the like.
Conventionally, in the case where leaf vegetables and the like, and fruits and vegetables and the like are cultivated in an environment control production equipment such as a green house or an artificial illuminating cultivation chamber, such a cultivating system is general as to keep, to adequate values, various conditions including a light, temperature, humidity, gases and nutrient element, in order to hasten or expedite growth of the vegetables and to produce the vegetables high in quality.
Under such environmental conditions as to accelerate abrupt growth, however, there arise such problems on cultivation as not to be sufficiently covered by the conventional culture technique. As one of the problems, there is a tipburn that is one of physiological disorders. The tipburn is one of calcium deficiency decreases. This symptom is susceptible to appear in lettuce, cabbage, Chinese cabbage, celery and strawberry. There may be a case also in the outdoor cultures that the tipburn is caused if the same conditions are complete or uniform. The vegetables appearing in the tipburn symptoms are considerably reduced in its market price. A mechanism is as follows in which the tipburn is generated in the lettuce.
The reason why the tipburn is caused in the lettuce is rupture of laticifer and collapse or breakdown of cells. However, a direct cause for inducing this tipburn is a reduction in a supply quantity of calcium to growing tissues.
The calcium is deteriorate in movement within the bodies of plants. Accordingly, once the calcium has been accumulated in old leaves, there is less that the calcium is moved to new leaves. Further, in the vicinity of a growing point, there is less in a quantity of transpiration because of insufficient ventilation, so that an absorption ability of nutrient element is reduced. Thus, under such a condition that the total quantity of calcium absorption is less in the entire bodies of plants, deficiency first appears in the vicinity of forward ends of new leaves. Since the tipburn is destruction of leaf tissues, parts in which tipburn is once caused are not again recovered. The tipburn parts stop in growth, and gradually become brown so that the tipburn parts wither and die. From such reason, the tipburn appears primarily on new leaves in the vicinity of the growing point.
In order to solve such problem on cultivation represented by the tipburn, it is essential to improve the cultivating technique. Various approaches have been done to the improvement in the culturing technique from such positions as breeding, utilization of chemical adjusting materials, improvement in culture-solution compositions, and so on. Even if such techniques have been used, however, a method of preventing such tipburn has not still been discovered.
By the way, the culture equipment described above has such an advantage that the culture equipment is not influenced by the outdoor weather conditions so that the optimum environment can be maintained. However, the conventional environmental control technique aims only at hastening or expedition of the growth rate, but is not utilized as means for solving the problems on cultivation.